An adult female polar bear, left, and two 1-year-old cubs walk over snow-covered freshwater glacier ice in Southeast Greenland in March 2015. (Kristin Laidre via AP)
As polar bears fight for survival because of disappearing Arctic sea ice, a new group of Greenland bears seems to have found an icy area that might permit a small population to “hang on.”
But the situation overall for the endangered polar bear species remains serious. Scientists say the animals are in danger of disappearing because of the effects of climate change.
A team of scientists recently studied a group of a few hundred polar bears in Southeast Greenland. These bears are genetically different and geographically separate from others.
What is unusual about these bears is that they survive even while having just 100 days a year when there is enough sea ice to hunt seals. In other places, polar bears need at least 180 days, usually more, of sea ice for them to effectively hunt. When there is no sea ice, bears often do not eat for months.
Sea ice is frozen ocean water. With limited amounts of this ice, the Southeast Greenland polar bears use freshwater ice masses called icebergs. The icebergs – created from the shrinking Greenland ice sheet – serve as hunting grounds, scientists say.
A study on the new finding recently appeared in the publication Science.
The scientists, however, are not sure if the bears might be surviving because they are smaller and have fewer babies than other polar bear populations.
Kristin Laidre was the lead writer of the study. Over nine years, Laidre followed, studied and tested the all-white bears - usually from a helicopter.
“These polar bears are adapted to living in an environment that looks like the future,” Laidre said.
But Laidre added that Greenland is special. “Most bears in the Arctic don’t have glacial ice,” she said.
Laidre explained, “We project large declines of polar bears across the Arctic and this study does not change that very important message.”
The population of polar bears is on the southeast part of Greenland, where there are no towns. For years scientists believed these bears were part of the same population that existed in Northeast Greenland.
But they are not, Laidre said. Wind and other conditions around 64 degrees North make it next to impossible for bears to move north of that point, she added.
While most bears travel 40 kilometers over four days, the Southeast Greenland bears go about 10 kilometers in the same amount of time, the study found.
“They just stay in the same place for years and years,” Laidre said.
Beth Shapiro was the co-writer of the study. She said genetic testing has shown that the Southeast Greenland bears are different from other polar bear populations.
In general, the Southeast Greenland bears are thinner than other Arctic bears, with females weighing about 185 kilograms. This compares to weights of about 199 to 255 kilograms for bears in other parts of the North American Arctic, Laidre said.
The Southeast Greenland bears also often have fewer babies, she added. This could be because they are so isolated and do not get as many chances to reproduce.
“They’re not reproducing as much as other individuals... They’re not as healthy as other individuals who are in a better habitat,” Shapiro said.
She used the term oasis – meaning a safe place that is surrounded by something unpleasant - to describe where the bears live.
“So it’s kind of an oasis maybe, but it’s not a happy oasis,” Shapiro said. “It’s a I’m-struggling-to-get-by-but-just-making-it kind of oasis.”
Words in This Story
hang on – phr v. to barely keep surviving
ice sheet – n. a permanent layer of ice covering a large area of land, especially a polar region
species – n. biology : a group of animals or plants that are similar and can produce young animals or plants : a group of related animals or plants that is smaller than a genus
adapt – v. to change (something) so that it functions better or is better suited for a purpose
isolate – v. to put of keep someone or something in a place or situation that is separate from others
habitat – n. the place or type of place where a plant or animal naturally or normally lives or grows